Electric discharge lamps



June 1957 E. J. G. BEESON 2,795,724

ELECTRIC DISCHARGE LAMPS Filed March 26, 1954 sf SocKets for holding and Connecting lamp/T Invent-or: V Eric J. G Beeson,

His Atoo ney ELECTRIC DISCHARGE LAMPS Eric J. G. Beeson, Rugby, England, assignor to General Electric Company, a corporation of New York Application March 26, 1954, Serial No. 418,970

Claims priority, application Great Britain April 8, 1953 2 Claims. (Cl. 313-198) This invention relates to gaseous electric discharge lamps capable of emitting flashes of actinic radiation such as are useful in photography, and particularly to constructions of such lamps in which the discharge takes place in a glass tubular envelope in the shape of a U.

In lamps of this type the tubular glass envelope has an ionizable gaseous atmosphere therein, electrodes sealed into its ends, and a triggering electrode engaging the out side of the envelope for facilitating the ignition of the lamp.

In the specification of British Patent No. 677,044 a lamp of this character is disclosed which is mounted on a base having plug-in contacts to which are connected the lamp electrodes and the wire to which the triggering potential is applied. A lamp of this type is also disclosed and claimed in U. S. Patent No. 2,624,023, issued December 30, 1952, and assigned to the assignee of this application.

An object of the present invention is to decrease the cost of manufacturing the lamp, at the same time retaining the plug-in properties of the lamp. Further objects and advantages of the invention will appear from the accompanying drawing and the following description of a species thereof.

According to the invention the electrodes sealed through the ends of the U-shaped envelope of the lamp extend externally of the envelope and are formed as contact elements adapted for plugging directly into sockets forming part of holder for supporting the lamp. The lamp has a triggering electrode which is connected to a bridge extending between, and clamped to, the limbs of the envelope adjacent its ends. A contact projecting from the holder is adapted to engage this clamp when the lamp is plugged into the holder.

The triggering electrode may be constituted by a wire wound round, and extending between, the limbs of the envelope and connected at each crossing point to a conducting support which is connected, at one end, to the bridge and at its other end is clamped to the envelope at its bight.

A preferred embodiment of the invention is illustrated in the accompanying drawings, in which Fig. l is a front view of the improved U-shaped gaseous discharge tube; and

Fig. 2 is a side view of the tube shown in Fig. 1. In each case the holder with which the tube is to be employed is shown in chain-dotted lines.

Referring to the drawings, the discharge tube comprises a U-shaped envelope 1 of glass having sealed into the ends thereof electrodes 2, 3 which are preferably in the form of stout tungsten wires. The electrodes project outwardly from the envelope and the ends of the electrodes external to the envelope constitute contact elements adapted for plugging directly into sockets forming part of a holder for supporting the lamp. To this end, the outer ends of the electrodes are preferably provided with cylindrical sleeves 4, 5 which may be of brass and which are connected to the outwardly projecting ends of the elec- States Patent 0 ice trodes by brazing or similar means. Thus, as illustrated in the drawing, sleeves 4, 5 provide pin-type terminals extending axially of the limbs of the envelope and rigidly secured in place. The arrangement allows the lamp readily to be plugged into a suitable socket, and at the same time assures a rigid mounting and reliable connections.

The triggering electrode is in the form of a thin metal wire 6 wound round, and extending between, the limbs of the envelope 1 and connected at each crossing point to a conducting thick metal wire support 7; the fine wire thus forms continuous loops around both limbs of the envelope, as clearly illustrated in Fig. 1. The support 7 is connected, at one end, to a bridge 8 in the form of a metal strap which extends between, and is clamped to, the limbs of the envelope adjacent its ends; the other end of the support 7 is clamped to the envelope at its bight. To make contact with the trigger electrode, the holder with which the lamp is to be employed may be provided with a contact member which engages the bridge 8.

Such a holder for the lamp is indicated in chain-dotted lines at 9, and is provided with the usual spring contact sockets into which the contacts 4, 5 are adapted to be plugged. The holder is also provided with a spring contact member 10 adapted to engage the bridge 8 when the lamp is plugged into the holder.

By thus forming the envelope of the lamp with its own plugging connections, material is saved and cost reduced. Even though it is necessary to furnish the holder with a spring contact to engage the triggering electrode instead of with a plain socket contact, a form of plug or other contact for the triggering electrode would, in the case in which the lamp is provided with a cap or base, be necessary on the cap to provide the required connection to the holder.

While the internal electrodes 2 and 3 have been described as extending externally of the envelope so as to constitute contact elements for the lamp, it will be understood of course that the electrodes 2 and 3 may be separate elements provided with the usual current inlead wires which extend through and are fusion sealed with the ends of the glass envelope 1 and that the external portions of said inleads may be provided with the contact members 4 and 5.

What I claim as new and desire to secure by Letters 7 Patent of the United States is:

1. An electric discharge lamp comprising a sealed U- shaped light-transmitting tubular envelope, internal electrodes at the ends of the limbs of said envelope, electric inleads for said internal electrodes extending externally of the envelope, the external portions of said inleads constituting electrical contacts for said lamp, an electrically conducting bridge member extending between and engaging the limbs of said U-shaped envelope adjacent said internal electrodes, an external electrode on said envelope comprising a fine metal wire looped continuously around both limbs of said U-shaped envelope and electrically connected at one end to said bridge member which con stitutes an electrical contact for said external electrode, and an electrically conducting elongated support attached at one end to said bridge member and at the other to the bight of said envelope, said fine wire being fastened to said support at the point where it crosses thereover in passing from one limb of the envelope to the other.

2. An electric discharge lamp comprising a sealed U- shaped light-transmitting tubular envelope, internal electrodes at the ends of the limbs of said envelope including relatively stout wire inleads sealed axially through said ends and extending externally of the envelope, tubular pin-type terminals rigidly fastened to the external portions of said wire inleads immediately beyond the seals through the envelope ends and extending axially of the limbs of said envelope, said pin-type terminals constituting electrical contacts for said internal electrodes, an electrically'conducting bridge memberin the formof a metal strap extending between and engaging the limbs of said envelope adjacent said internal electrodes, an external electrode on said envelope comprising a line in'etal wire looped continuously around both limbs of said envelope and electrically connected at one end to said bridge mem- Ber serving as an electrical contact for said external electrode, and an electrically conducting elongated support fastened at one end'to said bridge meniber and extending between said envelope limbs and fastened at its other end to the hight of said envelope, the metal wire con- 4 stituting said external electrode being fastened to said support at-the points where it'crosses thereover in passing from one limb of the envelope to the other.

References Cited in the file of this patent UNITED STATES PATENTS 2,042,195 Scott May 26, 1936 2,228,327 Spanner Jan. 14, 1941 2,217,697 Grier 2 4-"; Mar. 31, 1942 'Germeshati sen Apr. 30, 2,624,023 Noel et a1. Dec. 30, 1952 

